The desire to maintain a youthful appearance by reducing wrinkles and fine lines in the skin is an important issue in human society. Many techniques have been designed to achieve the above issue, one of which is skin rejuvenation using, for example, fractional photo-thermolysis. This fractional photo-thermolysis may, for example, be used for treatment of fine lines, wrinkles, unevenness of pigmentation and dyschromia. Fractional photo-thermolysis is based on creating micro-zones of damage inside skin tissue within areas or volumes of unaffected skin tissue. The treatment either removes (ablative treatment) or thermally damages skin tissue in the micro-zones. The type of treatment, the density of the micro-zones and the depth of the micro-zones are chosen in relation to the skin treatment required and the type of skin to be treated.
A device for such fractional photo-thermolysis treatment is disclosed in US patent application US 2012/0197357. In this patent application an apparatus, in particular a handheld apparatus, is disclosed for delivering optical energy. The apparatus includes an optical pattern generator inside the housing, which includes a rotatable component configured to continually rotate about a rotation axis in a single direction and to deflect the optical beam during rotation to divide the electromagnetic radiation into pulses that propagate from the housing toward the skin surface and form the fractional pattern at the skin surface. Too high a dose of optical energy locally deposited into the skin tissue is highly undesirable during these treatments, because this may lead to complications and even health risks of the person being treated, as well as to social downtime. Therefore, the known fractional photo-thermolysis treatment device comprises a controller which comprises several safety measures to prevent such damage from occurring. However, these safety measures significantly reduce the freedom to operate the known treatment device, as a result of which the ease of use of the known treatment device is reduced.
Consequently, a drawback of the known fractional photo-thermolysis treatment device is that the safety measures limit the freedom to operate this known treatment device.
US 2012/0283709 discloses a treatment device for fractional laser-based skin treatment, comprising a radiation source, a beam scanning system, and a control system to control the radiation source and the beam scanning system. The control system includes a displacement sensor for determining the displacement of the device relative to the skin and/or a motion/speed sensor for determining the speed, rate or velocity of the device moving or gliding across the skin. The controller is configured to control the beam radiation source and/or the beam scanning system in dependence on the displacement, speed, rate or velocity measured by the displacement sensor or motion/speed sensor.